1. Field of Invention
The present invention relates generally to support devices for hinged panels which are mounted on a vehicle, such as the hood thereof. More particularly, this invention concerns support devices which allow an operator to secure a panel in an opened position, and initiate a downward movement thereof so that the panel swings smoothly towards a closed position with a rate of descent which is controlled by the support device.
2. Related Art Statement
Hinged closure panels on automobiles take various forms, such as a hood, a deck lid, a glove box, an ash tray cover, and a sun roof. Some of such closure panels are at rest in a generally horizontal position and are movable therefrom toward a vertical position. Especially in the case of heavier panels such as the vehicle hood, it is desirable to support the panel securely in a fully opened position, to control the rate of descent of the panel, and to lock it in a closed position. Additionally, there may be a need to assure that such a panel is firmly held in the opened position so as to increase its resistance to wind on a gusty day, regardless of vehicle attitude.
One approach to such design needs is to provide a gas cylinder which is positioned under the closure panel. These approaches are somewhat effective in controlling the rate of descent of the panel. Nevertheless, in some devices there remains a need to support the panel reliably at the opened position, because such devices may diminish in effectiveness as gas escapes over time. Additionally, their performance characteristics may be influenced by environmental parameters, such as ambient heat and pressure.
Since gas pressure is affected by temperature, conventional gas cylinder lift assists may need to be installed in automobiles after paint operations to reduce their exposure to heat. It would therefore be desirable to have a support device for a hinged panel which could be installed with other body panels in the metal body shop without suffering deterioration during exposure to heat generated during subsequent painting operations.
The use of spiral or helical members to translate rotary into axial displacement is illustrated in such references as U.S. Pat. No. 2,408,181 issued to Simonton; U.S. Pat. No. 2,432,096 issued to Hammond; U.S. Pat. No. 3,709,522 issued to Olson; U.S. Pat. No. 4,493,469 issued to Holobaugh. However, none of these references disclose a support device for a hinged panel mounted on a vehicle where the panel is angularly displaceable between an opened position through intermediate positions to a closed position. Nor does any other known art teach the use of helical mating surfaces on a support device for a hinged panel which enable an operator to cause the panel to be secured in an opened position, or move it downwardly through intermediate positions at a controlled rate of descent.